Just to share some hands on experience with the unit: very important to have the proper damping factor between cans and Aune X7S relatively high output impedance. It seems a bit unstable and in my case any of the 32 ohms cans showed quite a bit of coloration when switched between single ended and balanced output. I think it will be sensible amp for cans at least 120ohms or higher balanced. Secondly, there is noticeable hiss starting at around 2 o'clock with balanced output. Last but not least HE400i were definitely too bright with the X7S.

I used 2 different iFI DACs and a TEAC UD-301. Dip switches were are the default 0db setting. I think fundamentally damping factor is too low for low impedance cans. I wish they publish the output impedance.

Headfonia's findings were similar to my experience: http://www.headfonia.com/review-aune-x7s-shooting-the-moon/2/

Finally found some reference to output impedance being @ 10ohm SE and 20ohm balanced. I wish Aune adds it to the published specs for it is probably one of the most important parameters in an amp.

Here is the source: https://translate.googleusercontent.com/translate_c?depth=1&hl=en&prev=search&rurl=translate.google.com&sl=pl&sp=nmt4&u=http://www.audiofanatyk.pl/recenzja-wzmacniacza-aune-x7s/&usg=ALkJrhjhC3nxTocw_fMBwN5CnyqX7xf04w